91.
The gaseous envelope around the earth is known as atmosphere. The lowest layer of this is extended upto $$10km$$ from sea level, this layer is __________. A
stratosphere
B
troposphere
C
mesosphere
D
hydrosphere
Answer :
troposphere
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No explanation is given for this question. Let's discuss the answer together.
92.
Which of the following practices will not come under green chemistry? A
If possible, making use of soap made of vegetable oils instead of using synthetic detergents.
B
Using $${H_2}{O_2}$$ for bleaching purpose instead of using chlorine based bleaching agents.
C
Using bicycle for travelling small distances instead of using petrol/diesel based vehicles
D
Using plastic cans for neatly storing substances.
Answer :
Using plastic cans for neatly storing substances.
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Plastics are non-biodegradable, hence are not environmental friendly.
93.
Match the column I with column II and mark the appropriate choice.
Column I (Pollutants)
Column II (Source)
a.
Toxic heavy metals
1.
Domestic sewage
b.
Microorganisms
2.
Industries and chemical factories
c.
Organic wastes
3.
Chemical fertilizers
d.
Plant nutrients
4.
Discharge from food processing factories
A
a - 1, b - 3, c - 2, d - 4
B
a - 3, b - 4, c - 1, d - 2
C
a - 4, b - 2, c - 3, d - 1
D
a - 2, b - 1, c - 4, d - 3
Answer :
a - 2, b - 1, c - 4, d - 3
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94.
Identify the wrong statement in the following : A
Chlorofluorocarbons are responsible for ozone layer depletion.
B
Greenhouse effect is responsible for global warming.
C
Acid rain is mostly because of oxides of nitrogen and sulphur.
D
Ozone layer does not permit infrared radiation from the sun to reach the earth.
Answer :
Ozone layer does not permit infrared radiation from the sun to reach the earth.
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Ozone layer acts as a shield and does not allow ultraviolet radiation from sun to reach earth. It does not prevent infra-red radiation from sun to reach earth, thus option (D) is wrong statement and so it is the correct answer.
95.
Which forms the part of hazy fumes of photochemical smog? A
$$S{O_2}$$
B
Nitrogen dioxide
C
$$PAN$$ formation
D
Aldehydes
Answer :
Nitrogen dioxide
96.
Eutrophication causes A
increase in nutrients
B
increase in dissolved salts
C
reduction in dissolved oxygen
D
reduction in water pollution
Answer :
reduction in dissolved oxygen
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Eutrophication results in reduction of dissolved oxygen.
97.
The dissolution of ozone layer causes ozone hole in the blanket surrounding the atmosphere. What are the ill effects of ozone hole? A
Greenhouse effect
B
Global warming
C
Acid rain
D
$$UV$$ rays reaching the earth
Answer :
$$UV$$ rays reaching the earth
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Ozone hole would allow the harmful $$UV$$ rays of sun to reach the earth which cause skin cancer.
98.
Which of the following reactions is taking place resulting in discolouration of marble of the buildings like Taj Mahal? A
$$CaC{O_3} + {H_2}S{O_4} \to $$ $$CaS{O_4} + {H_2}O + C{O_2}$$
B
$$CaC{O_3} + 2HCl \to $$ $$CaC{l_2} + {H_2}O + C{O_2}$$
C
$$CaC{O_3} + {H_2}O \to $$ $$Ca{\left( {OH} \right)_2} + C{O_2}$$
D
$$CaC{O_3} \to CaO + C{O_2}$$
Answer :
$$CaC{O_3} + {H_2}S{O_4} \to $$ $$CaS{O_4} + {H_2}O + C{O_2}$$
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High level of sulphur and nitrogen oxides cause acid rain which reacts with marble to decolourise it.
99.
Lichens do not like to grow in cities A
because of absence of the right type of algae and fungi
B
because of lack of moisture
C
because of $$S{O_2}$$ pollution
D
because natural habitat is missing
Answer :
because of $$S{O_2}$$ pollution
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Because lichens are very sensitive to sulphur dioxide and in cities the amount of
$$S{O_2}$$ is high, so they do not grow in cities.
100.
Which of the following is not a part of green chemistry? A
Photochemistry
B
Sonochemistry
C
Nuclear chemistry
D
Biochemistry
Answer :
Nuclear chemistry
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Green chemistry is the way by which the pollution or deterioration to the environment is minimised, nuclear chemistry is not the part of green chemistry.